1. Field of the Invention
The present invention relates to techniques for correcting the distortion of a projected image which may occur when there is a difference between an original image as captured or created and the shape of the projected image generated when the original is projected.
2. Description of the Related Art
Due to the difference between a projecting method used to capture or create an original image and a projecting method used to project the original image onto a planetarium, or when the image is projected onto a spherical screen, the projected image may suffer from distortion. To reduce or eliminate this distortion of the projected image, JP-2002-14611-A discloses a technique for correcting a original image created for each pixel position before projection.
The technique disclosed in JP-2002-14611-A comprises post-conversion pixel position data generating means and projected image data generating means for sequentially delivering projected image data sequentially supplied from image data supply unit from an output unit to an associated video projector for projection onto a spherical screen. The post-conversion pixel position data generating means converts each pixel position on an original image to a position at which a projected image is less distorted or free from distortion to sequentially generate post-conversion pixel position data, based on a certain consistent correlation between the original image which is the basis of incoming projected image data and distortion of the projected image which is produced when the original image is projected onto the spherical screen. The projected image data generating means sequentially generates projected image data for each frame after the pixel position conversion from applied projected image data and the post-conversion pixel position data generated by the post-conversion pixel position data generating means, and emits the resulting image from an output device for projection, thereby mitigating the distortion of the image projected onto the spherical screen.
In the technique disclosed in JP-2002-14611-A this technique entails the means for converting each pixel position on an original image to a position at which a projected image is less distorted or free from distortion to sequentially generate post-conversion pixel position data, based on a certain consistent correlation between the original image which is the basis of incoming projected image data and distortion of a projected image produced when the original image is projected onto the spherical screen, and a memory having a capacity large enough to store each and every transformed point generated by the means as individual data, as well as a special projector.
In addition, since the technique is developed for a planetarium system and therefore dedicated to a spherical screen, no applicability is taken into consideration for other screens having projection surfaces in arbitrary shapes.